hey guys,
i got a '01 DTS with 144k, took it in to get the coolant flushed yesterday and the guy said i had an oily sludge in my resivor. on the way home (15 miles) i noticed the temp gauge creeping up. finally it came up saying the temp was hot so i pulled over and let it cool down. then went for a while again trying to limp it home. it also started chugging and got worse as i went. i stopped again and took the radiator cap off to let it cool down. that helped a little and finally made it.

guess my question is, i hate to say it but is the reason i have oil in there a bad hg? or is there something else it could be? could they of done something when i got it flushed that would of caused the overheating?? if it is hg's i guess i will have to tear into it but dont really want to, cause i know its a pain in the a$$!!

let me know what you think guys.

Submariner409

04-09-09, 08:27 AM

Oil in the coolant and overheating. Rough running.

Limber up your engine stand and toolbox. It's top end overhaul time.

97EldoCoupe

04-09-09, 09:17 AM

Oil in the coolant- very rare with a bad HG but I've seen it 2-3 times. The block has an oil pressure passage on each bank going through to the cylinder head, and if the head gasket fails just right, it can be pumping oil into your coolant passages. Check for any unusual oil leaks as well between the engine and tranny- a bolt failing in this area can also cause what looks to be a bad rear main seal, when in reality it's just the HG/bolts.

Also, you don't have the oil cooler option on your DTS do you? I don't think any Devilles/DTSs ever had the engine oil cooler. Not that i know of. If you do, it could be a corrupted oil cooler in the rad. Doubtful, but don't overlook it.

Seems like a lot of people are having problems after getting the system flushed/refilled. And it seems like there's a lot more 00+ cars beginning to fail. I'm doing a 2002 STS very soon and a 2003 STS is also on the waiting list now.

pontiacsouth

04-09-09, 09:40 AM

sub, thats kinda what i expected to hear :crying2:

97, i dont see any oil leaks, i dont think i have an oil cooler on my car...

guess its time to get dirty...

Ranger

04-09-09, 11:21 AM

You do have an oil cooler. It is inside the right radiator side tank. I would bet that is where your oil & coolant are mixing.

pontiacsouth

04-09-09, 11:32 AM

so do you think the radiator is bad? :banghead:

Ranger

04-09-09, 11:39 PM

From what I'm reading, that would be my guess.

chubbyranger

04-12-09, 07:38 AM

Is it possible the guy who did the flush mistook the surge tank deposits from sealant tabs as oil sludge? If the cooling system wasn't purged properly after the flush could the overheat could have been caused by air pockets? Is the car continuing to overheat?

Ranger

04-12-09, 10:20 AM

Is it possible the guy who did the flush mistook the surge tank deposits from sealant tabs as oil sludge? If the cooling system wasn't purged properly after the flush could the overheat could have been caused by air pockets? Is the car continuing to overheat?

That's a distinct possibility.

codewize

04-12-09, 10:43 AM

Damn, I'm always late on these things but my thoughts are right in line with most of the rest.

Deposits in the tank are probably from seal tablets, HG failure very very rarely allows coolant / oil to mix and seeing how it happened after a flush I'm also going to blame the radiator.

I don't know how many times we have to say around here, DON'T FLUSH anything just drain and refill. Don't flush the rad, don't flush the trans just don't flush because the next thing you're flushing is money.

Destroyer

04-12-09, 09:03 PM

Seems like a lot of people are having problems after getting the system flushed/refilled. And it seems like there's a lot more 00+ cars beginning to fail. I'm doing a 2002 STS very soon and a 2003 STS is also on the waiting list now.I called that and everyone said I'm crazy. Guess the different "thread pitch" didn't work out after all. :alchi:

pontiacsouth

04-13-09, 08:51 AM

Is it possible the guy who did the flush mistook the surge tank deposits from sealant tabs as oil sludge? If the cooling system wasn't purged properly after the flush could the overheat could have been caused by air pockets? Is the car continuing to overheat?

i dont know, i will talk to the guy that did it today. when i picked up the car it was fully warmed up, the gauge was at 12 o'clock as it usually is. i got about 5 miles down the road before it started getting hot.

i havn't drove the car since i brought it home. kinda waiting to get info on what could of happened before i tried to fix the problem.

pontiacsouth

04-13-09, 08:54 AM

one more thing, dont know if its related or not but, sometimes this last winter when the car was fully warmed up and i was at a stoplight the heater wouldnt blow warm air, but when i got going again it would blow warm again. anyways, dont know if thats related or what...

Submariner409

04-13-09, 09:07 AM

A heater core which gets cold at idle and warm at speed is a sure indication of air or partial blockage in the coolant or piping. With the car running, warm, in P and the heater on, temp at max, if the air then cools down at idle, try bringing the rpm up to around 2,000 for 30 seconds. Does the heater get warm ?? Where does the temp gauge go during this experiment ??? Can you hear any coolant flow (gurgling) down in the console area ?? If your heater heats and cools with rpm and you can hear coolant flow, then the chances are that you have low coolant, air trapped in the system, or maybe a bad thermostat. A failed head gasket puts combustion gasses into the coolant system and overpressurizes it, so coolant blows out the cap pressure relief and the engine overheats.

pontiacsouth

04-13-09, 12:36 PM

A heater core which gets cold at idle and warm at speed is a sure indication of air or partial blockage in the coolant or piping. With the car running, warm, in P and the heater on, temp at max, if the air then cools down at idle, try bringing the rpm up to around 2,000 for 30 seconds. Does the heater get warm ?? Where does the temp gauge go during this experiment ??? Can you hear any coolant flow (gurgling) down in the console area ?? If your heater heats and cools with rpm and you can hear coolant flow, then the chances are that you have low coolant, air trapped in the system, or maybe a bad thermostat. A failed head gasket puts combustion gasses into the coolant system and overpressurizes it, so coolant blows out the cap pressure relief and the engine overheats.

i'll try this tonight. i have had the car almost 2 years and havn't added coolant to it. every time i checked it it was where it was supposed to be. i have never heard gurgling from the car before. last winter it would cool off when idling and once you got over 1000 rpm it would warm up again. i have to check it out and get back to you. thanks all for your help...

codewize

04-13-09, 03:49 PM

See now this is the issue I have going on the 4.5 forum. I thought for sure there was a clog somewhere but there's not. Now we're swearing that something is wrong with the water pump. This is on a 4.5 but same symptom.

I also keep getting told that a clogged heater core will not cause a car to overheat because of the bypass.

Maybe we can work this out together? Have any of you participated in my 4.5 posting?

Ranger

04-13-09, 10:31 PM

I also keep getting told that a clogged heater core will not cause a car to overheat because of the bypass.

That is correct. It will only cause a lack of cabin heat.

codewize

04-14-09, 08:04 PM

OK So I'm definitely dealing with a flow problem then, as we're discussing.

That is correct. It will only cause a lack of cabin heat.

pontiacsouth

04-15-09, 08:23 AM

ok, finally got a chance to "play" with the car last night.

i started off by removing the hoses that went to the overflow tank and made sure they were clear. all were ok. then i took the radiator hose off and added 2 tablets of bars leak, reattached the hose and topped off the overflow tank. it took about a gallon to get to the cold mark. i started the engine and ran it for about 1/2 hour and the coolant temp was 198 according to my obd2, but the bottom radiator hose was still cold. it was blowing cold air, i rev'd it up to about 1500 and it started to blow warm air and continued to do so. so i took a walk with my son and came back after running it for about an hour. the hose was still cold and the temp was the same, 198+-. both fans were running by the way.

what temp is the thermostat supposed to open at? could that be the problem?

Ranger

04-15-09, 11:12 AM

I believe the thermostat starts to open at 180. Sounds to me like you have air in the system or are not purging it all out. Rev it to 3-4K a few times to purge it.

pontiacsouth

04-15-09, 11:55 AM

if the stat opens at 180, shouldn't the lower hose be warm like the top one was?

i thought the coolant level would go down, but it didn't budge at all after running about an hour.

i could try it again tonight, reving it up like you described

:hmm:

Submariner409

04-15-09, 12:40 PM

The thermostat for your car begins to open at 188 and is fully open at 206. If both fans were running, I'll bet they were in Slow, and you had some sort of AUTO or HVAC mode commanded which ran the A/C compressor. Any time the compressor runs, so do the fans, and the radiator is big enough to completely cool the engine under those conditions. If the heater was also commanded on, then the combination of air conditioning, fans, and idle would probably never require the thermostat to fully open. A normal 1999-2004 Northstar FWD package will run at 195 - 208 all day long on the highway with no fans on. I think that the fans do not run, ever, above 45 mph. Read the GM Factory Service manual. The surge tank "floats" on the system - there is really little flow through the tank other than the purge line input - so coolant rises and falls in the tank as engine heat changes. The airspace in the tank allows the system to pressurize to 18 psi (2001) in order to raise the 50/50 mix coolant boil point to about 265 degrees. 70/30 coolant (max concentration) boils at 276 degrees at 18 psi. The Northstar cooling system is unique in that the thermostat/lower hose is the last section to heat up. If you look at the thermostat housing you'll see a smaller (1" ?) line which taps off and heads toward the firewall. That's the thermostat bypass and heater line.

pontiacsouth

04-15-09, 01:02 PM

ok, i did have the air on and the heater on almost full. the fans were running slow.

so i should turn the heater/ac off and rev it up in order to make the thermostat open and purge the system?

how long should it take to purge all the air out once the stat opens?

thanks for your input guys! :D

Submariner409

04-15-09, 01:12 PM

Set the system to manual, a/c OFF, and heater temp to minimum setting on both driver and passenger (if equipped). Make sure the surge tank is half full, COLD. Drive normally here and here, as in doing errands. Later, after the car cools check the coolant level, adding only enough to bring it back to half full.

Don't forget that these systems use air blend to control temperature, not heater core coolant flow. The heater core has full flow at all times, so if there's an air bubble in the core, the purge will occur fairly quickly. Did you make sure that the little purge line, from the thermostat area of the crossover manifold to the surge tank, is "pissing" coolant into the tank just after cold start ?? If not, then the nipple at the tank or crossover is clogged.

pontiacsouth

04-15-09, 01:34 PM

Set the system to manual, a/c OFF, and heater temp to minimum setting on both driver and passenger (if equipped). Make sure the surge tank is half full, COLD. Drive normally here and here, as in doing errands. Later, after the car cools check the coolant level, adding only enough to bring it back to half full.

Don't forget that these systems use air blend to control temperature, not heater core coolant flow. The heater core has full flow at all times, so if there's an air bubble in the core, the purge will occur fairly quickly. Did you make sure that the little purge line, from the thermostat area of the crossover manifold to the surge tank, is "pissing" coolant into the tank just after cold start ?? If not, then the nipple at the tank or crossover is clogged.

ok, i'll try this. guess i'm just used to working on my old pontiacs, this is all new to me. thanks much for your help!

pontiacsouth

04-16-09, 07:42 AM

alright, i took the car out last night, drove it 18 miles. i had the ac off and heater set on low. drove 10 miles and the temp was at 200 and the lower hose wasnt warm yet. turned around and headed home, the the temp climbed to 245 so i turned the heater on full to cool it down, it eventually came down to 200 so i turned the heat down again, when i got home it was up to 230 again. checked the hose and still was no where near as warm as the upper hose. i heard a bubbling sound coming from where the lower hose connects to the block and heard bubbling coming from the resivoir tank. i checked the tailpipes for water and they were dry and sooty as normal. the level of antifreeze didnt go down any. pulled the crossover tube off the tank and stuck it inside, started the car and it just spurted and didnt really flow much, just spit out some coolant. when i stopped after 10 miles i also reved it up to 3k a few times. i live in the sticks, so i was driving the back roads going 45-55.

i also noticed that the car was "pulsing" when i was at a steady speed like around 55. the rpms would go up a little and go down, kinda felt like the tranny was slipping or something, dont know how to really explain it.

i tried to pull the codes off the obd2 and there were none.

so you think its the stat thats bad or????????

Submariner409

04-16-09, 08:38 AM

Now it sounds like thermostat.

pontiacsouth

04-16-09, 10:05 AM

Now it sounds like thermostat.

That's what i thought too. its only like $13 for a new one so i guess i'll try that. i'll do that this weekend and let you know what happens...

pontiacsouth

04-20-09, 08:31 AM

ok, put a new thermostat and radiator cap on the car, filled the tank up to the cold level, took the car into town, about 8 miles going 60 mph, the temp was at 210 when i stopped in town for gas. the lower hose was still not warm. i headed back home, about 2 miles out of town it got hot, up to about 250, i pulled over and let it cool off and nursed it back home. the lower hose was still not hot. there are no codes.

do you think that the radiator is plugged or why isnt the stat opening? :confused:

a guy here at work had a blazer with the dex-cool in it and said he had sluge in the resivoir tank and it plugged up his radiator and he needed a chemical flush to clean the sluge build up out.

codewize

04-20-09, 09:19 AM

Just for the record, as a last resort, I'm having my water pump pulled tomorrow obviously replacing it if the impeller seems damaged in any way.

If not I have no idea where to turn. I'll definitely keep you informed because it does sound like we have the same problem on 2 different cars.

I did the stat, I did the chemical flush, I replaced the radiator, etc. So at this point for you I would say sit tight until I have more info or you'll go down this road of throwing money at it. Let learn something from the money I've already thrown away.

On a side note, between the things I wanted to repair and the things that cropped up along the way I have close to $3500 into this 20 year old car now and I still can't drive it.

pontiacsouth

04-20-09, 10:13 AM

i know a guy that works at a 'lac dealership in milwaukee, i'm going to call him tonight and see what he thinks. i dont want to throw parts at it hoping it will fix it.

if i find anything out i'll post it.

to be continued....

Ranger

04-20-09, 12:06 PM

Test the coolant.

tateos

04-21-09, 06:09 PM

I called that and everyone said I'm crazy. Guess the different "thread pitch" didn't work out after all. :alchi:

I agree with Destroyer ( and I think AJ also) on this - the design is prone to HG problems.

I agree with Jake that the engines can in most cases be repaired properly and for a reasonable sum and many more years of service can be enjoyed from the car, IF YOU LIKE THE IT AND WANT TO KEEP IT.

codewize

04-21-09, 09:44 PM

Turns out that the impeller on my pump was completely gone. I elaborated in my 4.5 coolant flow post.

My car is fixed :) and is for sale

Destroyer

04-21-09, 10:22 PM

i know a guy that works at a 'lac dealership in milwaukee, i'm going to call him tonight and see what he thinks. i dont want to throw parts at it hoping it will fix it.

if i find anything out i'll post it.

to be continued....It's the damn H/G issue! 9 out 10 posts that are in any way, shape or form about about coolant issues always turn out to be head gaskets. Don't throw parts at it, have it tested and then either junk it or fix it.

pontiacsouth

04-22-09, 07:49 AM

I'm going to get the test kit after work and find out if its the h/g or not.

on a side note, wouldn't the stat still open up if the h/g was bad? it would make sense to me that it would open and the lower hose would be hot like the upper? guess i'm not exactly sure how the cooling system works....

DTECKBAUER

04-22-09, 11:20 AM

Well, I have to chime too. I have the same problems, 2000 Deville,last three times i had it out it overheated.I drove it to work (about 18 miles) about ten miles into the trip it started geting hot,turned heat all the way hot, blower on high,....nothing but cold air.sometimes if i goosed the gas it would start blowing warm air for a little bit but then went cold again. Now i am in uptown Madison and late for work and did not want to stop to cool down although it did not say it any where on the dash i think i was in limp mode the last three or four blocks. parked the car,opened the hood,could see that i had been blowing out coolant from the over flow.Cooling fans were running but the air comming up from the fans,was cold.... So at lunch i added just shy of a galon of coolant. On the ride home it did the same thing,only now was not in such a rush, i stopped to cool down alittle,and noticed that the rad. hose going to the drivers side of rad was not hot, air was cold blowing up from cooling fans,when they shut off i could here water trying to get by the stat, I also think that I may have oil in my coolant. when i got the car i put new coolant and a package of GM seal tabs, i put five in the upper hose. i over dosed it those five were enough for a twenty qt. system i think mine is like 10 or 11 qts.so i know the tabs will change the looks of the coolant but it looks black.

chubbyranger

04-22-09, 08:51 PM

Well, I have to chime too. I have the same problems, 2000 Deville,last three times i had it out it overheated.I drove it to work (about 18 miles) about ten miles into the trip it started geting hot,turned heat all the way hot, blower on high,....nothing but cold air.sometimes if i goosed the gas it would start blowing warm air for a little bit but then went cold again. Now i am in uptown Madison and late for work and did not want to stop to cool down although it did not say it any where on the dash i think i was in limp mode the last three or four blocks. parked the car,opened the hood,could see that i had been blowing out coolant from the over flow.Cooling fans were running but the air comming up from the fans,was cold.... So at lunch i added just shy of a galon of coolant. On the ride home it did the same thing,only now was not in such a rush, i stopped to cool down alittle,and noticed that the rad. hose going to the drivers side of rad was not hot, air was cold blowing up from cooling fans,when they shut off i could here water trying to get by the stat, I also think that I may have oil in my coolant. when i got the car i put new coolant and a package of GM seal tabs, i put five in the upper hose. i over dosed it those five were enough for a twenty qt. system i think mine is like 10 or 11 qts.so i know the tabs will change the looks of the coolant but it looks black.

This sounds bad on a few fronts. The coolant should not look black. Oil in the coolant is a possible failure of the oil cooler in the radiator side tank. Adding coolant means its going somewhere and if you do not have a leak its likely out the exhaust. Have the coolant tested for exhaust gasses.

pontiacsouth

04-23-09, 07:21 AM

Well, I have to chime too. I have the same problems, 2000 Deville,last three times i had it out it overheated.I drove it to work (about 18 miles) about ten miles into the trip it started geting hot,turned heat all the way hot, blower on high,....nothing but cold air.sometimes if i goosed the gas it would start blowing warm air for a little bit but then went cold again. Now i am in uptown Madison and late for work and did not want to stop to cool down although it did not say it any where on the dash i think i was in limp mode the last three or four blocks. parked the car,opened the hood,could see that i had been blowing out coolant from the over flow.Cooling fans were running but the air comming up from the fans,was cold.... So at lunch i added just shy of a galon of coolant. On the ride home it did the same thing,only now was not in such a rush, i stopped to cool down alittle,and noticed that the rad. hose going to the drivers side of rad was not hot, air was cold blowing up from cooling fans,when they shut off i could here water trying to get by the stat, I also think that I may have oil in my coolant. when i got the car i put new coolant and a package of GM seal tabs, i put five in the upper hose. i over dosed it those five were enough for a twenty qt. system i think mine is like 10 or 11 qts.so i know the tabs will change the looks of the coolant but it looks black.
------------------------------------------------------------------------
sounds pretty much like what mine is doing, but my antifreeze is still orange. i went to napa to get the test last night and they have to order it. I'll test it tonight and pray for the best...

pontiacsouth

04-24-09, 07:02 AM

well, I got the test kit from Napa, warmed the car up till the coolant was about 190 degrees, stuck the test thing in the opening, held it in there for a minute while pumping it. the liquid didn't turn yellow, the color did change to sort of a greenish-blue.

since it wasn't even close to being yellow, the h/g's should be fine right? is that normal for it to change to a greenish color?

what should my next step in diagnosing the problem? i know the water pump is ok, the bypass hose isnt blocked, put a new stat and cap on it. can the radiator be blocked?

DTECKBAUER

04-24-09, 09:47 AM

How many miles on that coolant that you tested? I did the test on mine and got the same color, i thought more of a green coolant color,but since i did not have very many miles on the coolant Ranger says test it after it's been in a while, but if i have oil in the coolant now(witch i'm not 100% sure it dose, but it is black)it will fail the test now,right?

Ranger

04-24-09, 09:47 AM

held it in there for a minute while pumping it.
Pumping what? I'm not exactly sure how it works, having never used one, but you didn't dip it in the coolant did you? I think you are only sampling the air above it.

DTECKBAUER

04-24-09, 09:52 AM

I sampeled the air on mine.

Submariner409

04-24-09, 10:10 AM

The tester pulls whatever "gas" is in the surge tank airspace, in the form of bubbles, up through a chemical liquid mixture. If there's exhaust gas (hydrocarbons) in the airspace, it mixes chemically with the test liquid and turns it a very noticeable yellow color.

Looks like the bubbles in an old Christmas tree "bubble light".

Mark C

04-24-09, 10:17 AM

The tester has a bulb on the top of it that you pump. It basically tries to pull a vacuum on the air space on top of the water in the surge tank and draws that air though the test fluid. On my 00 deville I can pump that thing up until the bulb won't reinflate when I let go of it and my fluid just barely changed from blue to a greenish blue. Still way more blue than greenish blue. I do beleive the engine is in the early stages of a HG going bad at 170K miles.

But mine never overheats (sits right at 198 per my OBDII software on my laptop), barely uses coolant (I can smell coolant in the engine compartment and have a minor leak somewhere, but I can't find it yet) , and my exhaust pipes are dry as a bone. My tank also retains a small amount of pressure when the coolant is at ambient pressure if i haven't taken the cap off in a while (like more than a month).

My second Seville (the one I'm pulling the engine on now) would turn the tester yellow in about 3 pumps on the tester, but it would idle in the driveway for 90 minutes before it would begin to heat up. Never got to drive it any distance but the previous owner said it would heat up in about 5 minutes and smoke white smoke like a freight train.

So even if your headgasket is beginning to go, it should not be bad enough yet to cause the car to overheat.

And yes if you really have oil in the water then the tester will indicate the same thing as a blown headgasket because you do have hydrocarbons in the coolant, thats what oil is.

pontiacsouth

04-24-09, 10:24 AM

How many miles on that coolant that you tested? I did the test on mine and got the same color, i thought more of a green coolant color,but since i did not have very many miles on the coolant Ranger says test it after it's been in a while, but if i have oil in the coolant now(witch i'm not 100% sure it dose, but it is black)it will fail the test now,right?

I got the coolant flushed a few weeks ago, probably about 50 miles on the coolant by now, with all the testing. my coolant doesnt really look like it has oil in it but has a little bit of black around the egde of the surge tank, probably from those tablets.

pontiacsouth

04-24-09, 10:37 AM

The tester has a bulb on the top of it that you pump. It basically tries to pull a vacuum on the air space on top of the water in the surge tank and draws that air though the test fluid. On my 00 deville I can pump that thing up until the bulb won't reinflate when I let go of it and my fluid just barely changed from blue to a greenish blue. Still way more blue than greenish blue. I do beleive the engine is in the early stages of a HG going bad at 170K miles.

But mine never overheats (sits right at 198 per my OBDII software on my laptop), barely uses coolant (I can smell coolant in the engine compartment and have a minor leak somewhere, but I can't find it yet) , and my exhaust pipes are dry as a bone. My tank also retains a small amount of pressure when the coolant is at ambient pressure if i haven't taken the cap off in a while (like more than a month).

My second Seville (the one I'm pulling the engine on now) would turn the tester yellow in about 3 pumps on the tester, but it would idle in the driveway for 90 minutes before it would begin to heat up. Never got to drive it any distance but the previous owner said it would heat up in about 5 minutes and smoke white smoke like a freight train.

So even if your headgasket is beginning to go, it should not be bad enough yet to cause the car to overheat.

And yes if you really have oil in the water then the tester will indicate the same thing as a blown headgasket because you do have hydrocarbons in the coolant, thats what oil is.

ya, i could only pump that rubber thing on the tester so much before it wouldnt reinflate anymore. so i pumped it as much as i could but let it sit on there for over a minute.

mine will stay around 198 all day if i let it idle, but once i take it into town and back (8 miles) its overheating.

i dont think there is any oil in there, its just the residue from the tabs.

my lower rad hose still isnt getting hot so there must be something f'd up in the system...

AMENCADDY

04-24-09, 12:58 PM

Damn, I'm always late on these things but my thoughts are right in line with most of the rest.

Deposits in the tank are probably from seal tablets, HG failure very very rarely allows coolant / oil to mix and seeing how it happened after a flush I'm also going to blame the radiator.

I don't know how many times we have to say around here, DON'T FLUSH anything just drain and refill. Don't flush the rad, don't flush the trans just don't flush because the next thing you're flushing is money.
DARN IT! and I just flushed my throne. :histeric: Knew I should've read the forum first.

Submariner409

04-24-09, 05:51 PM

:eek: It probably needed a courtesy flush anyway............

AMENCADDY

04-24-09, 07:15 PM

:eek: It probably needed a courtesy flush anyway............
It was a desperate move on my part. The drain and refill would've taken way too long and the only other option was a plug in the nose. It is just way too hard for me to hold my breath that long. I'm confident that I did the right thing in this case. All the experts agree.:worship:

codewize

04-25-09, 12:59 PM

LOL you guys kill me.

pontiacsouth

04-27-09, 06:39 AM

so....any thoughts on what could be the problem if its not the h/g's??

btw, i don't know if its supposed to do this but the test liquid i used turned blue again after i let it sit overnight.

pontiacsouth

04-28-09, 09:27 AM

i took the surge tank off and cleaned it and checked for cracks. took the radiator hoses off, stuck a garden hose in both hoses and ran water thru it. ran water in the hose that goes to the surge tank, took the crossover tube off also and blew that off. the stat opened when i put it in boiling water. the impellers on the water pump felt ok.

is there anything else i can check while i have it appart?
any ideas?

pontiacsouth

04-29-09, 09:22 AM

Just for the record, as a last resort, I'm having my water pump pulled tomorrow obviously replacing it if the impeller seems damaged in any way.

If not I have no idea where to turn. I'll definitely keep you informed because it does sound like we have the same problem on 2 different cars.

I did the stat, I did the chemical flush, I replaced the radiator, etc. So at this point for you I would say sit tight until I have more info or you'll go down this road of throwing money at it. Let learn something from the money I've already thrown away.

On a side note, between the things I wanted to repair and the things that cropped up along the way I have close to $3500 into this 20 year old car now and I still can't drive it.
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i tore the cover off the water pump last night and mine looked ok, the belt, tensioner were ok too. i have to put the stat back in it tonight and refill the system/purge it. i dont know what else i can do to it. if this doesnt work its going in to get fixed. i'm sick of driving my blazer, its not the same as driving the 'lac.

pontiacsouth

05-06-09, 07:00 AM

is everyone out of ideas??? :hmm:

zonie77

05-06-09, 04:28 PM

Early HG failure causes a lot of confusion when trying to diagnose. You may still have some tension on the gaskets. At idle cyl pressure is lower and may not give a real definitive test. Try stressing the engine more before the test. Possibly high idle or some hard acceleration before testing.

Did you flush the radiator well?

pontiacsouth

05-07-09, 12:25 PM

Early HG failure causes a lot of confusion when trying to diagnose. You may still have some tension on the gaskets. At idle cyl pressure is lower and may not give a real definitive test. Try stressing the engine more before the test. Possibly high idle or some hard acceleration before testing.

Did you flush the radiator well?

ya i flushed it well, i took it back to the place that flushed, they said they would look at it for free, have to see what they say...

pontiacsouth

06-08-09, 12:31 PM

well, the shop i had it flushed at tested it and they said it was ok, they recommended changing the thermostat. i tested it with the napa tester and it didnt turn yellow. can something get stuck in the passages inside the engine therefore restricting coolant flow??

jimzilla

06-08-09, 06:01 PM

I usually test lower radiator hose after car has been running a while. If its cold, therm isnt opening. The predicament with N* engines with slight HG failure is that the combustion gases push into the water jacket creating a bubble. Typical symptoms are that you see water temp change quickly, and...that lower hose is cold. The air bubble is an insulator and both thermal sensors (thermistor for gage and pellet for thermostat) are not in intimate contact with water. I have either used an older SBC 160F thermostat (yes the rubber seal will still work) or drill an eighth inch hole into thermostat to see if that is the problem. I orient the hole towards the top during reassembly. This will not cure HG problem but will help engine stay cooler.
I have also made circuit to turn on fans by sensing water temp, and I turn them on sooner than N* PCM does with hole in thermostat and I have people driving for over a year with HG problems. You can also turn fans on manually from from HVAC controls in diagnostic mode to see if it will help before spending dime one.
I have seen a few earlier (97+) N* with oil but slight in reservoir with HG problems.

pontiacsouth

06-16-09, 07:23 AM

I usually test lower radiator hose after car has been running a while. If its cold, therm isnt opening. The predicament with N* engines with slight HG failure is that the combustion gases push into the water jacket creating a bubble. Typical symptoms are that you see water temp change quickly, and...that lower hose is cold. The air bubble is an insulator and both thermal sensors (thermistor for gage and pellet for thermostat) are not in intimate contact with water. I have either used an older SBC 160F thermostat (yes the rubber seal will still work) or drill an eighth inch hole into thermostat to see if that is the problem. I orient the hole towards the top during reassembly. This will not cure HG problem but will help engine stay cooler.
I have also made circuit to turn on fans by sensing water temp, and I turn them on sooner than N* PCM does with hole in thermostat and I have people driving for over a year with HG problems. You can also turn fans on manually from from HVAC controls in diagnostic mode to see if it will help before spending dime one.
I have seen a few earlier (97+) N* with oil but slight in reservoir with HG problems.

Well, I finally picked it up from the dealer that checked it out. i drove it home about 20 miles doing about 55 mph on the back roads and it was about 80 degrees out. the temp gauge didnt get over the 12 o'clock mark while driving. when i got home i let it run for a few minutes and the temp started going up. the lower hose was still cool. I'll try what you suggested and see if that makes a difference. any other ideas??

Submariner409

06-16-09, 08:55 AM

If you drove 20 miles at 55 and then sat in the driveway, it is perfectly normal for the gauge to climb to about 12:30 or 1:00 (224 degrees) before the fans go to slow.

The Northstar has a very efficient cooling system, so I would fully expect the lower radiator hose to be not much more than fairly warm before the fans come on. In addition to the radiator there is a lot of heater and bypass piping in the engine compartment, and the front area of the car is designed to move one hell of a lot of air over the engine at 55. The thermostat in your engine is not fully open until 206 degrees and the car runs at 196 on the highway all day.

pontiacsouth

06-18-09, 07:11 AM

If you drove 20 miles at 55 and then sat in the driveway, it is perfectly normal for the gauge to climb to about 12:30 or 1:00 (224 degrees) before the fans go to slow.

The Northstar has a very efficient cooling system, so I would fully expect the lower radiator hose to be not much more than fairly warm before the fans come on. In addition to the radiator there is a lot of heater and bypass piping in the engine compartment, and the front area of the car is designed to move one hell of a lot of air over the engine at 55. The thermostat in your engine is not fully open until 206 degrees and the car runs at 196 on the highway all day.
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i had my obd2 code reader hooked up the whole way home and it was around 200 degrees the whole way home. i let it run a minute in the driveway and the temp went up to 235, then i shut it off. there is still the "check coolant level" message coming up. there is coolant in the tank at the correct level.